Pakistan President Asif Ali Zardari will visit Turkey on Friday to attend the second trilateral summit. Afghan President Hamid Karzai will be a part of that meeting.

The summit will focus on "important development dimensions in the bilateral process including joint economic projects (and) regional and trilateral economic and trade matters," said a statement from the Foreign Office.

During his stay in Istanbul, Zardari will have separate bilateral meetings with Turkish President Abullah Gul and Karzai.

The regional situation, including the tensions between India and Pakistan, are expected to figure in the talks between Zardari and Karzai, sources said.

Meanwhile, UN Secretary General Ban Ki-Moon on Thursday called Zardari and discussed the regional situation.

The first trilateral summit was held in Ankara in April last year.